The invention relates to a gusseted bag made of a flexible weldable material with a closed bottom end that at the inside top end is provided with a reclosable device, where side gussets that are inserted between the two bag walls that form the front bag wall and the rear bag wall stretch from the bottom end to the top end and terminate at a distance below the upper edge of the bag walls and thus define a top area of the bag without side gussets, where the reclosable device is formed between the two bag walls.
Gusseted bags of this kind are used for packing various fill materials in piece, granule or powder form that are generally withdrawn in individual portions after removing a final closure of the bag, e.g., a welding seam, that has been placed at the outer edge area of the top end of the bag by the fill material company. The reclosable device, e.g., in the form of an interlocking profile strip closure device, enables the user to reclose the bag each time after goods are withdrawn, or to reopen it for withdrawing fill material. In general, it is desired to design the reclosable device of the bag in an aroma-proof manner to retain the quality of the fill material. For this reason, it is necessary to provide a tight seal for the upper ends of the side gussets as well, such that with known gusseted bags of the type in question, the upper ends of the side gussets are closed as well when the bags are manufactured.
In a known gusseted bag of the above mentioned kind, this is accomplished in that the upper ends of the side gussets are closed by a separately welded sealing strip underneath the reclosable device, where said sealing strip, when welded, at the same time holds the respective side gusset end to one of the two bag walls. Although such weld connections can be made easily with regard to the bag material and the material of the sealing strips, because these materials are generally, at least in the area of the surfaces that are to be welded together, made of thermoplastic synthetic materials that can be welded well to one another, however, the use of separate sealing strips results in additional material expenditures, which adversely effects the manufacturing costs of a mass-produced item such as the gusseted bag in question. In addition, the circumstance that the sealing strips hold the upper ends of the side gussets to the respective wall when establishing the weld connection results in a narrowing of the fill opening of the bag, that has a negative effect both on the fill speed during machine filling of the bag in the filling plant and with regard to the end user, for the ability to completely empty the bag.
The invention has the objective to create a gusseted bag of the type mentioned above, where a closure of the upper ends of the side gussets is formed in a simple manner in the course of the bag manufacturing and under avoidance of an increased material expenditure, where at the same time said closure has no adverse effect on the filling and emptying properties of the bag.
According to the invention, this objective is accomplished in that the upper ends of the side gussets are closed by being welded together to themselves and underneath the reclosable device reach freely into the inner space of the bag.
An increased material expenditure such as is necessary with the known sealing strips is avoided with the welding of the upper ends of the side gussets to one another subject to the invention, while due to the circumstance that underneath the reclosable device the closed side gusset ends reach freely into the interior space of the bag, an adverse narrowing of the fill opening of the bag, which at the same time is the emptying opening for the consumer, is avoided. This allows for a steady and quick filling of the bag in the filling plant because the filling material runs into the bag on both sides of the side gussets that are free at their upper ends. Along with that comes an optimal opening of the side gussets by spreading flat towards the outside during filling and when the fill level rises. The free side gussets prove advantageous from a consumer point-of-view, because they avoid corners in the opening area that would retain fill material residue when emptying the bag.
Depending on the material condition of the bag, welding the upper side gusset ends to themselves can be carried out easily by applying a closing weld seam, preferably in the area of the upper cutting edge of the side gusset ends, which may run transversely towards the bottom end, between their two material layers, or where the upper region of the side gusset ends is folded onto one of the two halves of each side gusset, and the welding of the standing side gusset end to itself is carried out with the folded end region and the adjacent side gusset half. The upper end region of the side gussets may be folded along a folding line that starts at the outer edge of the side gusset halves and runs transversely to the bottom end, such that the folded end region exhibits the shape of a right angled triangle with a hypotenuse that is directed transversely to the inside of the bag.
The arrangement of the reclosable device in the top area of the bag that is free of side gussets ensures its easy attachment, e.g., by a welding process during the manufacture of the bag. Thus, the reclosable device can be attached to the interior side of the bag, for example, in the form of interlocking profile strips made of thermoplastic synthetics, in the simple manner that is familiar from flat bags. Such interlocking profile strips that can be closed by interlocking in a groove and tongue fashion are generally known. However, within the scope of the design of the invention, the reclosable device can also be formed by closure strips in the form of velcro-type strips or as a sliding or zipper-type closing device. Furthermore, within the scope of the invention it is also possible to select a reclosable device that is formed by a strip of a continuously adhesive material or a pressure sensitive material applied to the inside of the front and/or back wall of the bag. With the bag subject to the invention, this freedom of selection in the design of the reclosable device is ensured by having the reclosable device at a location entirely separate from the closure of the upper side gusset ends in the top area of the bag that is free of side gussets.
Additional features and advantages of the invention will become readily apparent from the claims and the following description in connection with the drawings, where an exemplary embodiment of the subject of the invention is schematically illustrated.